This invention relates generally to poured concrete wall systems and, more particularly, concerns a method and apparatus for forming insulated concrete walls.
Concrete walls can be formed in various ways. Some are constructed from concrete blocks on footings, some can be made from prefabricated members, and others can be formed by pouring or pumping in uncured concrete between rigid forms. The wall forms are generally planar structures and typically are made of wood, aluminum, steel, or combinations of these materials. For poured walls, two series of coplanar wall forms are held in a spaced apart, generally parallel relationship to create the cavity which will form the concrete wall. The wall forms are typically held in the correct spaced-apart relationship by a series of retaining ties extending between the form assemblies. The retaining ties commonly include holes formed in each end whereby pins are used to join adjacent coplanar forms together. Once the wall forms are in place, concrete is poured into the cavity between the forms and, after the concrete has cured, the forms are disassembled for reuse. The protruding ends of the ties are then broken off.
Poured concrete walls have many benefits over other types of concrete walls. They can be quickly constructed, are relatively easy to construct, are versatile, and durable. One drawback of all concrete walls however, is that they are poor insulators. A typical concrete wall has an insulating "R" value of approximately 1.0.
To improve the insulating qualities of concrete walls, several methods have been developed for incorporating polystyrene sheets within the concrete wall, or on one or both exterior surfaces of the concrete wall. A concrete wall with 2.5 inches of polystyrene insulation on one side has an insulating "R" value of approximately 13.0. Similarly, a concrete wall with 2.5 inches of polystyrene insulation on both exterior surfaces of the wall has an insulating "R" value of approximately 26.0.
Present methods of insulating concrete walls, however, suffer from the drawback of adding considerable time and labor to construct the concrete wall. One known method in particular uses special parallel foam sheets held together by metal members. This system is difficult and time consuming to set up, and requires additional external supports to prevent the foam walls from bulging due to the weight of the concrete. Another drawback of some insulated concrete wall systems is that they require unique and unconventional wall forms. This also can add additional time, labor and, ultimately, cost to the finished concrete wall.